In radiation therapy, a living body such as a human or an animal is exposed to radiation from the outside of the living body, and tumors to be treated in the radiation therapy exist in the body in many cases. Thus, radiation therapy is always accompanied by a side effect, i.e. exposure of skin as a passage for radiation.
Skin after radiation therapy is irritated to turn red due to occurrence of an acute skin reaction in a radiation exposure region. Therefore, the radiation dose to tumors in radiation therapy is limited by the skin reaction. The skin reaction is also closely related to the quality of life (QOL) of a patient after therapy. Thus, if a skin reaction caused by radiation therapy can be predicted beforehand, the dose of exposure to radiation in the therapy can be easily decided, and the quality of life of a patient after therapy can be improved.
Here, examination of patent documents shows that a radiation monitor system for radiation therapy has been proposed (see Patent Document 1). The purpose of the system is to estimate the adsorbed dose of radiation applied to a patient undergoing radiation therapy.
However, the system is intended to measure the absorbed dose of exposure to radiation in practice, and is not intended to predict a skin reaction to radiation exposure beforehand.